1. Field of the Invention
The present invention relates to the field of hydraulically operated clamps. In particular, the invention is concerned with an hydraulic pull cylinder having a piston rod connected to the shaft of a wedge-shaped clamp operator received in a complementally shaped opening defined in a clamp block having a shiftable jaw. Retraction of the piston rod pulls the operator toward the base of the block in order to shift the jaw to a clamping position to hold a workpiece.
2. Description of the Prior Art
In the prior art, manually operated clamps are used to hold workpieces during machining and other manufacturing operations. These prior art clamps include a clamp block positioned on a support plate. The block includes a shiftable jaw. A bolt with a wedge-shaped head is received into a recess in the block and extends through the block into a threaded hole in the support plate. An alien wrench or the like is used to tighten the bolt into the hole. The bolt head spreads the block in order to extend the jaw and pin a workpiece against a support wall. When operations on the workpiece are completed, the wrench is used to reverse the bolt and release the workpiece from the clamp.
These prior art manually operated clamps are time-consuming and tedious to use on a repetitive basis. As a result, manufacturing productivity is less than optimum.